The invention relates to an undersea connection system for connecting together electrically in sealed manner at least three undersea electric cables capable of transporting electric current at high voltage or very high voltage, and in particular direct current (DC).
Transporting electrical energy by means of undersea cables, in particular when it takes place at high voltage DC or very high voltage DC, makes it possible to transport electricity over long distances in a marine environment and at high currents, and therefore at very high powers. In an electricity transmission network including undersea portions, it is often necessary to be able to interconnect a third offshore component to a link between two points that may already be in existence. For example, it may be desirable to connect an offshore wind farm to an electricity network that includes an undersea cable.
Nevertheless, making such a connection in a marine environment requires major constraints to be taken into account. The undersea connection system must be capable of withstanding hydrostatic pressure at the sea bottom without damaging the cable, and without allowing water to infiltrate into the electrical insulation system. The system must be capable of withstanding major mechanical stresses while it is being installed, while nevertheless being light in weight and compact. The connection needs to be capable of being installed quickly and it must benefit from reliability that is sufficient to enable it to operate over a very long lifetime, which may for example be at least 30 years.